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Nick Piggin 7e675137a8 mm: introduce pte_special pte bit ... s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory model (which is more dynamic than most). Instead, they had proposed to implement it with an additional path through vm_normal_page(), using a bit in the pte to determine whether or not the page should be refcounted: vm_normal_page() { ... if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { if (vma->vm_flags & VM_MIXEDMAP) { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; #else if (!pfn_valid(pfn)) return NULL; #endif goto out; } ... } This is fine, however if we are allowed to use a bit in the pte to determine refcountedness, we can use that to _completely_ replace all the vma based schemes. So instead of adding more cases to the already complex vma-based scheme, we can have a clearly seperate and simple pte-based scheme (and get slightly better code generation in the process): vm_normal_page() { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; return pte_page(pte); #else ... #endif } And finally, we may rather make this concept usable by any architecture rather than making it s390 only, so implement a new type of pte state for this. Unfortunately the old vma based code must stay, because some architectures may not be able to spare pte bits. This makes vm_normal_page a little bit more ugly than we would like, but the 2 cases are clearly seperate. So introduce a pte_special pte state, and use it in mm/memory.c. It is currently a noop for all architectures, so this doesn't actually result in any compiled code changes to mm/memory.o. BTW: I haven't put vm_normal_page() into arch code as-per an earlier suggestion. The reason is that, regardless of where vm_normal_page is actually implemented, the *abstraction* is still exactly the same. Also, while it depends on whether the architecture has pte_special or not, that is the only two possible cases, and it really isn't an arch specific function -- the role of the arch code should be to provide primitive functions and accessors with which to build the core code; pte_special does that. We do not want architectures to know or care about vm_normal_page itself, and we definitely don't want them being able to invent something new there out of sight of mm/ code. If we made vm_normal_page an arch function, then we have to make vm_insert_mixed (next patch) an arch function too. So I don't think moving it to arch code fundamentally improves any abstractions, while it does practically make the code more difficult to follow, for both mm and arch developers, and easier to misuse. [akpm@linux-foundation.org: build fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Carsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		17 years ago
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m32104ut	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
m32700ut	m32r: remove dead config symbols from M32R code	17 years ago
mappi2	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
mappi3	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
opsput	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
Kbuild	…
a.out.h	aout: move STACK_TOP[_MAX] to asm/processor.h	17 years ago
addrspace.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
assembler.h	m32r: Rename STI/CLI macros	18 years ago
atomic.h	atomic.h: atomic_add_unless as inline. Remove system.h atomic.h circular dependency	18 years ago
auxvec.h	…
bitops.h	forbid asm/bitops.h direct inclusion	18 years ago
bug.h	…
bugs.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
byteorder.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
cache.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
cachectl.h	…
cacheflush.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
checksum.h	…
cputime.h	…
current.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
delay.h	Fix __const_udelay declaration and definition mismatches	17 years ago
device.h	…
div64.h	…
dma.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
elf.h	Cleanup asm/{elf,page,user}.h: #ifdef __KERNEL__ is no longer needed	17 years ago
emergency-restart.h	…
errno.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
fb.h	fbdev: detect primary display device	18 years ago
fcntl.h	…
flat.h	Binfmt_flat: Add minimum support for the Blackfin relocations	18 years ago
futex.h	…
hardirq.h	…
hw_irq.h	…
ide.h	ide: remove ide_init_default_irq() macro	17 years ago
io.h	…
ioctl.h	…
ioctls.h	m32r: enable arbitary speed tty rate setting	18 years ago
ipcbuf.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
irq.h	m32r: remove dead config symbols from M32R code	17 years ago
irq_regs.h	…
kdebug.h	move die notifier handling to common code	18 years ago
kmap_types.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
kvm.h	kvm: provide kvm.h for all architecture: fixes headers_install	17 years ago
linkage.h	…
local.h	local_t m32r use architecture specific cmpxchg_local	17 years ago
m32r.h	m32r: Define symbols to unify platform-dependent ICU checks	18 years ago
m32r_mp_fpga.h	…
m32102.h	[PATCH] m32r: support a synthesizable M32700 core	18 years ago
mc146818rtc.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
mman.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
mmu.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
mmu_context.h	[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction	18 years ago
mmzone.h	…
module.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
msgbuf.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
mutex.h	…
namei.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
page.h	CONFIG_HIGHPTE vs. sub-page page tables.	17 years ago
param.h	avoid overflows in kernel/time.c	17 years ago
pci.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
percpu.h	…
pgalloc.h	CONFIG_HIGHPTE vs. sub-page page tables.	17 years ago
pgtable-2level.h	m32r: fix pte_to_pgoff(), pgoff_to_pte() and __swp_type() macros	18 years ago
pgtable.h	mm: introduce pte_special pte bit	17 years ago
poll.h	Consolidate asm/poll.h	18 years ago
posix_types.h	asm-*/posix_types.h: scrub __GLIBC__	17 years ago
processor.h	aout: move STACK_TOP[_MAX] to asm/processor.h	17 years ago
ptrace.h	m32r: convert to generic sys_ptrace	18 years ago
resource.h	…
rtc.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
s1d13806.h	…
scatterlist.h	Add CONFIG_DEBUG_SG sg validation	18 years ago
sections.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
segment.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
semaphore.h	Generic semaphore implementation	17 years ago
sembuf.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
serial.h	…
setup.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
shmbuf.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
shmparam.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
sigcontext.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
siginfo.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
signal.h	core: remove last users of empty FASTCALL macro	17 years ago
smp.h	Remove hardcoding of hard_smp_processor_id on UP systems	18 years ago
socket.h	[NET]: Introducing socket mark socket option.	17 years ago
sockios.h	[NET]: Introduce SIOCGSTAMPNS ioctl to get timestamps with nanosec resolution	18 years ago
spinlock.h	…
spinlock_types.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
stat.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
statfs.h	…
string.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
syscall.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
system.h	Fix m32r __xchg	17 years ago
termbits.h	m32r: enable arbitary speed tty rate setting	18 years ago
termios.h	m32r: enable arbitary speed tty rate setting	18 years ago
thread_info.h	m32r: Update sys_rt_sigsuspend	17 years ago
timex.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
tlb.h	…
tlbflush.h	remove unused flush_tlb_pgtables	18 years ago
topology.h	…
types.h	remove strict ansi check from __u64 in asm/types.h	18 years ago
uaccess.h	[PATCH] fix sparse warnings from {asm,net}/checksum.h	18 years ago
ucontext.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
unaligned.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
unistd.h	timerfd: fix remaining architectures	17 years ago
user.h	Sanitize the type of struct user.u_ar0	17 years ago
vga.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago
xor.h	[PATCH] m32r: cosmetic updates and trivial fixes	18 years ago